Hydrogen has been used unbonded from other elements for various purposes, in both a liquid and gaseous form. For instance, liquid hydrogen has been used in aerospace applications including manned space flight. In fact, liquid hydrogen was used as the fuel for the Saturn V rockets that propelled astronauts on their journey to the moon.
Hydrogen gas has also been used, though on a relatively small scale, for various purposes including in dirigibles and as a fuel for vehicles, such as automobiles and boats. Use of hydrogen as a fuel has been proposed on a larger scale because hydrogen typically produces much less pollution than alternative fuels and methods of energy storage. In fact, President George W. Bush advocated research into the use of hydrogen in vehicles in his 2003 State of the Union Address. It has been proposed that hydrogen may be used, for example, as a fuel for internal combustion engines, or in fuel cells. Hydrogen also produces more power per weight than other fuels, providing advantages in aerospace applications and other uses where weight is critical.
The product of combustion when hydrogen is burned is water vapor, so when pure hydrogen is burned in internal combustion engines, the traditional pollutants associated with fossil fuels, hydrocarbons, carbon monoxide, and air toxics, are not produced at all. In addition, the green house gas unavoidably produced by the combustion of fossil fuels, carbon dioxide, is also not produced at all in the combustion of hydrogen.
Using electrolysis, hydrogen has been produced by separating hydrogen and oxygen that form water. When used in its gaseous form, hydrogen has been stored at various pressures to reduce the amount of space that is required for storage. Electrolysis has typically been performed at atmospheric pressure, so compressors have been used to compress the hydrogen gas for storage. Such equipment and systems for the production of hydrogen have typically been powered by electricity, a substantial amount of which is used to drive the compressor. If hydrogen is to be used on a large scale, the amount of electrical power that will be used for this purpose will most likely be significant.
In addition, if hydrogen is to be used on a larger scale, the need exists for systems and equipment for handling, distributing, and dispensing hydrogen. For instance, if hydrogen is to be used on a larger scale in vehicles, a need exists for hydrogen dispensing or refueling stations. Such hydrogen refueling stations have been contemplated, for example, in U.S. Pat. No. 6,432,283, the content of which is hereby incorporated by reference. A need exists for suitable hydrogen refueling stations that may be located, for example, in urban areas where pollution levels are high, and hydrogen usage is likely to be particularly beneficial.
As mentioned above, at one time, hydrogen gas was used in dirigibles, and the famous Hindenburg disaster dramatized that hydrogen is quite flammable and can be dangerous if not handled in a safe manner. Thus, fire codes and other standards have required a high level of safety precautions for systems that handle or dispense hydrogen. For instance, systems for dispensing hydrogen have been very spread-out by requiring large “set-back” distances between hydrogen and buildings or other fuels, electric power lines, and areas accessible to the public, so that leaks of the flammable substance, and any resulting fires or explosions, are not likely to damage other equipment or endanger users or the public.
Storage tanks or pressure vessels were typically mounted next to the ground in a horizontal position, which further increased the amount of land required for a hydrogen refueling station. Pressure vessels were also typically penetrated on both ends providing multiple potential leakage points. Such hydrogen handling and dispensing facilities have typically been enclosed with high industrial fencing, for example, chain-link fencing, usually with barbed wire at its top to create a barrier for the public from the hazards of the gas. But such configurations are not suitable for applications in urban areas, for example, where land is limited and/or the value of land is high. If hydrogen is to become a fuel for motor vehicles, possibly including marine, fuel cell, or hybrid vehicles, then a need exists for hydrogen handling and dispensing systems (which may include hydrogen production and/or storage) to be compatible with existing motor vehicle refueling facilities located in light commercial areas generally accessible to the public.
In addition, hydrogen handling and dispensing systems have typically required elaborate active fire detection and suppression systems in the event of a leak which is ignited. In addition, such systems were typically custom designed and fabricated and tested on the site. These systems are expensive to construct, test, and maintain, and the fact that these activities have been performed at the site has increased their cost.
Thus, a need exists for hydrogen handling and dispensing systems that are safe and yet occupy a relatively small amount of land. A need exists for such systems to require a minimum amount of active fire detection and suppression systems, and that they be relatively simple, inexpensive to manufacture, easy to erect in the field, test, and maintain.
In addition, since large-scale hydrogen production and handling consumes a considerable amount of energy, a need exists to minimize the amount of energy that is required to produce and/or compress hydrogen, and a need exists to be able to conduct these activities (and consume the associated electrical power) during time periods when electricity is plentiful and inexpensive, for example, when other demands for electricity are relatively low. Since the production of electricity is much more economical when the production is at a steady and predictable rate, a need exists for systems that facilitate at least some control by the electrical power companies of when hydrogen is produced. On the other hand, hydrogen users need to be able to obtain hydrogen at times that are convenient to them. Thus, a need exists for hydrogen handling and dispensing systems to include pressure vessels configured to store hydrogen, from approximately the time that it is produced or compressed until it is distributed or dispensed. A need also exists that these pressure vessels occupy a relatively small amount of land, require a minimum amount of active fire detection and suppression systems, and be relatively inexpensive to manufacture, erect in the field, test, certify, and maintain.
Other needs also exist that may be apparent from this document to a person of skill in the relevant fields of this invention.